The present invention relates to a cooling apparatus, a cooling system and a method for cooling objects from a coating device. The invention relates, furthermore, to a coating plant with a drier and with a cooling system.
One of the techniques in widespread use in surface coating is painting. In painting, usually, a liquid or pulverulent coating substance or lacquer is applied thinly to the object to be painted. As a result of chemical and/or physical processes, a mostly continuous film is formed on the surface of the object. The film can then exert both technical actions, such as, for example, corrosion protection, and esthetic effects, such as, for example, a specific coloring.
A method in widespread use for producing specially high-quality and resistant paintings is stove enameling. In this case, the objects to be painted are heated before the painting operation. The lacquer applied to the objects can dry quickly and uniformly, thus resulting in a high-quality painting.
In the context of this application, the term “coating device” is to be understood as meaning a surface coating device, in which coating takes place either by means of a painting operation or by means of a powder coating operation. This term does not extend to a coating device in which an enameling operation or ceramic baking operation is carried out, this taking place at markedly higher temperatures which, as a rule, are considerably higher than 250° C.
It must be said that stove enameling is a highly energy-intensive method. On the one hand, the objects have to be heated in a drier or furnace after painting. This requires a considerable supply of energy, since the objects have to be heated as quickly as possible to the typical temperature of between 125° C. and 250° C., in particular between 150° C. and 200° C. After this stoving operation, the objects have to be cooled again, so as to be available for further machining processes. Heating and cooling give rise to a considerable outlay in energy terms, even though the object to be painted has approximately the same temperature at the entrance and at the exit of the coating plant (including the cooling).
In the past, it was proposed, for example for the cooling operation to introduce fresh air into a cooling apparatus and to allow the air heated by the objects to be cooled to flow into a storage depot which is to be heated. However, as a rule, the exhaust air from a cooling apparatus is not odor-neutral and may possibly also contain pollutant fractions which have remained.